Inkjet printing technology is non-impact printing, provides sharp and non-feathering images, and has great property such as water-fastness, light-fastness, optical density, storage stability and non-clogging, etc. Light-fastness property of dye compounds in an ink composition is essential to be applied in inkjet printing.
There are many dye compounds developed for inkjet printing; however, the current ink compositions still have many drawbacks. For example, U.S. Pat. Nos. 4,694,303, 5,062,892 and 7288142 disclose black ink dye compositions, including C.I. Food Black 2. However, these compositions have poor light-fastness. Taiwanese Patent No. I265193 and Taiwanese Patent Publication No. 200628564 disclose dye-mixed black ink compositions, which still have poor light-fastness. In order to improve light-fastness, U.S. Pat. No. 7,387,667 discloses a black dye composition; however, the light-fastness of this black dye composition needs to be further improved.
Accordingly, there exists an urgent need to develop a black ink composition having better property of dye compounds and meeting the foregoing requirements.